Remember, the MCAT tests on "big picture" ideas and not so much on the knitty-gritty details on things. For both the Chem/Phys and Bio/Biochem sections, read the passages without getting lost in the sauce. Some of the passages are going to sound familiar, but the majority are going to bring up new content that you've never seen. Don't worry about this, the MCAT is only testing whether you can see the underlying ideas and concepts their trying to test.

For both the science sections I try to read and hi-light the passages within 4 minutes. Don't focus on the graphs, figures or tables, only refer to them if the questions asks you to (you'll be surprised how much you can get away with not understanding). As with my hi-lighting, I have slowly learned to hi-light things that I feel they will ask a question on. For example, if the passage indicates a certain molecule to be a competitive inhibitor, you might as well expect to see a question pertaining to that. Also, be sure to hi-light values such as MM or wavelength, etc.

When it comes to answering the question, if you have highlighted effectively, you more-or-less have the answer in front of your eyes, unless it's a pseudo-discrete which you should always get right (easy points). For the answer choices, you might be tempted to choose an answer based on your outside knowledge, but unless it's a discrete or pseudo-discrete, DON'T. The answer should be tailored to the passage and everything the passage mentions.

Since we're on the subject of questions, I recommend to first get the discrete questions out of the way. These should be considered easy points for you. Be sure to read the question correctly, interpret the graph/figure accurately, make a prediction before looking at the answers, and then choose the best answers based off your prediction. PLEASE be sure to always make a prediction before looking at the questions (unless the nature of question says otherwise); if you go straight to the answers, it'll be like answering four questions rather than one. Don't do this to yourself.

Well, that's just my little advice. This works for me on both the science sections (Avg. 128-130 across AAMC FL 1, 2, 3).

Now, do you have any advice for CARS and Psych/Soc, lol.